    <style type="text/css">
        .letter_title {
            min-height: 30px;
            margin-bottom: 0;
        }
        #letter_content {
            padding: 5px;
            width: 518px;
        }
    </style>
    <div class="modal hide fade" id="letter_modal">
        <div class="modal-header">
            <button type="button" class="close" data-dismiss="modal">x</button>
            <h3 class="letter_title"></h3>
        </div>
        <div class="modal-body">
            <div class="control-group">
                <label class="control-label" for="letter_content">私信内容（不超过140字）</label>
                <div class="controls">
                    <textarea rows="5" id="letter_content"></textarea>
                </div>
            </div>
        </div>
        <div class="modal-footer">
            <span id="letter_res">发送成功</span>
            <a class="btn btn-primary" id="letter_modal_btn">发送</a>
            <a class="btn" id="letter_modal_cancel">取消</a>
        </div>
    </div>
    <script type="text/javascript">
        $(function() {
            $('#letter_modal_cancel').click(function() {
                $('#letter_modal').modal('hide');
            });
            $('#letter_modal_btn').click(function() {
                var user_id = $('#letter_modal .letter_title').attr('data-user-id');
                    content = $('#letter_content').val();
                if (content == '') {
                    // show error text
                } else {
                    $.post('msg/send', {
                        user_id: user_id,
                        content: content
                    }, function(data) {
                        if (data != 'error') {
                            $('#letter_res').removeClass().addClass('text-success').show();
                        } else {
                        }
                    });
                }
            });
        });
    </script>